【摘要】 为研究观测到的震前次声异常,提出了强地震发生前次声波异常信号产生的机理模型．该模型采用膨胀扩容孕震理论,将大气对流层与地质体作为一个动力学系统,采用瞬态有限元模拟方法计算分析了孕震末期地表变形及其产生的次声波和频率．结果表明,该模型的确能在空气中产生次声波,且次声波的主要频率是孕震体膨胀一收缩时间周期的倒数;孕震体收缩变形阶段产生的声压波幅远大于膨胀阶段．更多还原

【Abstract】 A mechanism model was proposed to explain the infrasound abnormality observed just several days before a strong earthquake. The model includes a layered rock geo-structure, air media and their interaction. A transient dynamic finite element analysis was carried out to simulate the formation of the infrasound. The waveform and frequency of the simulated infrasound were analyzed. The results show that the proposed model is able to produce infrasound and its frequency which agree well with that from the observed. The frequency is inversely proportional to the expansion-contracting period of the earthquake source body. The fluctuating range of the air pressure during the contracting is greater than that during the expansion.更多还原